Hang in there Jady.
Doctors almost always give you the "worst case scenario", and it is never good to hear, but hey need to cover their asses if they are wrong. So as far as they are concerned, every tumor is "life threatening".
My Uncle had brain tumors and had extensive surgery. Doctors told him that he had 6 weeks to live. Ten years later, he was still doing well. My Sister in law was diagnosed with breast cancer last November. Surgery, chemo and radiation therapy and she is going very very well.
Be positive. It is hard, but support is important.